Mask



FIG. 1 is a perspective view of an ornamental design of one embodiment of a mask showing our new design.

FIG. 2 is a front orthographic view thereof.

FIG. 3 is a rear orthographic view thereof.

FIG. 4 is a right side orthographic view thereof.

FIG. 5 is a left side orthographic view thereof.

FIG. 6 is a top orthographic view thereof; and,

FIG. 7 is a bottom orthographic view thereof.

The broken lines shown in FIGS. 1 and 3-7 are included for the purpose of illustrating environmental elements only and form no part of the claimed design. 

The ornamental design for a mask, as shown and described. 